Altered Tuning on 5 string (HELP!!!)

Okay..play a variety of American and European Spectors. We have been tuning to C standard. I tuned my five string up one half step. Now, they want to go up to D standard. If I detune the bass one whole step ( a d g c f) and just not use the lowest string, the thing sounds so sloppy and messy and is so hard to play accuratly...but if i try to tune up one and a half steps I feel like I'm gonna pop a string and / or damage my neck with the increased tension.......

Why don't you tune the bass normally and use the frets? Is it absolutely mandatory that you be in the same position as the guitar(s)? I would not be crazy about tuning my bass up a min3, the added tension on the neck, not the mention the playability or intonation would lead me to refuse.

hhahah first idea that came to mind lowphat. However, two major problems: 1) It's an extreme metal act which makes need for one open string being "d" and 2) I'm just not that good. Noone seems to be really responding to this thread, so I'll just ask:

How bout stringing the bass with a very heavey gauge 4 string set tuned down a full step, and add a high C tuned down a#?

hhahah first idea that came to mind lowphat. However, two major problems: 1) It's an extreme metal act which makes need for one open string being "d" and 2) I'm just not that good. Noone seems to be really responding to this thread, so I'll just ask:

How bout stringing the bass with a very heavey gauge 4 string set tuned down a full step, and add a high C tuned down B#?

It's important to be able to laugh at ourselves from time to time. That was a nice typo!
Now back to your issue: I can't say for sure without looking at your bass but switching to EADGC may require some added attention @ the bridge saddles and may warrant a full-on set-up due to reduced tension, altered string diam/height, intonation, etc. It's just hard to say, some basses just like it rough and will take anything you through at em', others require alot of attention and fiddling. Ultimately staying with your original ADGCF(whole step down) may be easier to achieve because of this(even though a set-up may be needed to achieve even that). IMO, any bass that has a decent B string can be dropped a whole step with the aid of a good set-up, the results may not be awesome, but they should be "serviceable". Something as simple as pick-up height adjustment can make the difference between a flabby fart and a note you can actual hear clearly.
As a last option you could drop everything BUT the B string and alter your fingerings accordingly but that could prove to be painfull.

thanx lowphat. Actually feeling like lightening the load a bit as far as gear is concerned, so I may dump one of my Spectors for a musicman sterling, which im told holds up quite well under detune. Will keep my other spector so I'll still have a five...